Add support for recent series of attiny MCUs

[JasXSL]

Is your feature request related to a problem? Please describe.
Thanks to megatiny you can use the newer series of attiny 1604, 3227 etc with arduino.

Describe the solution you'd like
Support for this library isn't too hard to add in. I forked the repo and added the following to io.h

#elif defined(__AVR_ATtinyxy4__) || defined(__AVR_ATtinyxy2__) || defined(__AVR_ATtinyxy6__) || defined(__AVR_ATtinyxy7__)
    /** The macro is defined when i2c Wire library is available */
    #define CONFIG_PLATFORM_I2C_AVAILABLE
    /** The macro is defined when SPI library is available */
    #define CONFIG_PLATFORM_SPI_AVAILABLE
    /** Define lcdint as smallest types to reduce memo usage on tiny controllers. *
     * Remember, that this can cause issues with large lcd displays, i.e. 320x240*/
    #define LCDINT_TYPES_DEFINED
    /** This is for Attiny controllers */
    typedef int8_t lcdint_t;
    /** This is for Attiny controllers */
    typedef uint8_t lcduint_t;

Nothing else was needed to run a simple 0.93" OLED. However, there are probably some things to think about before any eventual pull request:

• These microcontrollers come with a range between 2k and 32k of flash. Deciding where to use uint8_t or not may need consideration.
• SSD1306_WIRE_CLOCK_CONFIGURABLE may work. But setting the clock that high did cause other i2c devices to stop working, so I left it out.

[tpimh]

Thank you for your patch, it should be very useful.

Designing a circuit with ATtiny826 now, I'm wondering about the feasibility of using this library with it. My display is SSD1306 SPI 128x32. I guess, half RAM would be sacrifised for the display buffer (no double buffering).

I wonder what displays can be used with the 2k RAM microcontrollers.

[lexus2k]

@JasXSL Hi

Can you create pull request for you change?